JP6563921B2 - Process for producing polyunsaturated ketone compound - Google Patents

Description

<Field of Invention>
The present invention generally relates to a process for producing a polyunsaturated ester or polyunsaturated thioester compound. The invention further relates to the conversion of a thioester to its corresponding thiol and the conversion of the thiol to a polyunsaturated ketone. More particularly, the present invention relates to polyunsaturated thioesters, and hence subsequent thiols and polyhydrides, that substantially reduce or eliminate unwanted oxidation and cis / trans isomerization reactions in the manufacturing process. The present invention relates to a method for producing a polyunsaturated ketone compound.

<Background>
Many biologically active polyunsaturated fatty acids have one or more cis-configured carbon-carbon double bonds. Free radicals have been reported to support isomerization to the trans configuration which is less favorable for these bonds. Cis / trans isomerization can adversely affect polyunsaturated compounds intended for pharmaceutical use, for example, by reducing biological activity and / or complicating synthesis. For reference, C. Ferreri et al. (2007) Mol. Biotech. 37:19; Chatgilialoglu, C et al. (2002) Free Rrad. Biology & Medicine, 33: 1681; and WO 2002/100991.

Some, but not all, free radicals have been reported to support cis / trans isomerism of certain polyunsaturated compounds. The kinetics of radical mediated oxidation is believed to depend on several parameters such as the chemical nature of the unsaturated compound produced, temperature, pH, presence or absence of light, oxygen, and the like. Free radicals have been reported to occur naturally in the environment or as undesirable by-products produced from certain chemical reactions.
See, for example, Mengele, EA et al. (2010) Mos. Univ. Chemistry Bull 65: 210.

  Attempts have been made to reduce oxidation and reduce carbon-carbon double bonds and cis / trans isomerism. In one attempt, undesired oxidation of antioxidants such as octyl gallate, ascorbic acid, polyphenols, mercaptoethanol, beta-carotene or 2,6, -di-tert-butyl-4-mercaptophenol (BHT) Add to reaction. See Mengele, E.A, ibid; Klein, E and N. Weber (2001) J. Agric. Food Chem. 49: 1224; and Hung, W-L, et al. (2011) J. Agric. Food Chem. 1968.

  There are reports that certain polyunsaturated trifluoromethyl ketone compounds have useful biological activity. See, e.g., U.S. Patent No. 7,687,543; Huwiler, A et al. (2012) Br. J. Pharm. 167: 1691.

  A method for producing certain polyunsaturated ketones is disclosed. In one method that disclosed the synthesis of certain polyunsaturated trifluoromethyl ketones, the Mitsunobu type reaction was used to convert the alcohol to the corresponding thioester. A further chemical reaction describes that the polyunsaturated trifluoromethyl ketone (here, compound 18) was prepared in 71% y yield. See Holmeide, A and L. Skattebol (2000) J. Chem. Soc. Perkin Trans. 1: 2271.

  There is a general recognition that compounds intended for pharmaceutical use should be produced in high yields, eg 70% or more. Below a satisfactory yield, undesired by-products may be involved. These can be costly or difficult to remove from the main product (API), making further pharmaceutical development difficult. In addition, the Administration requires detailed analysis of by-products in compounds intended for pharmaceutical use. This requirement can make the cost of scale up prohibitively high.

  The Mitsunobu reaction has been reported to use phosphines and azodicarboxylates, among other reagents, and include the addition of new functional groups, often esters, to primary or secondary alcohols. The mechanism of the reaction is reported to be complex and there is controversy regarding the identification of reaction intermediates. See, for example, But, T and P. Toy (2007) Chem. Asian J. 2: 1340; and Swamy, K.C et al. (2009) Chem. Rev. 109: 2551. This makes it difficult to predict the results of certain Mitsunobu reactions.

International Publication No. 2002/100991 Pamphlet U.S. Patent No. 7,687,543

C. Ferreri et al. (2007) Mol. Biotech. 37:19; Chatgilialoglu, C et al. (2002) Free Rrad. Biology & Medicine, 33: 1681. Mengele, E.A et al. (2010) Mos. Univ. Chemistry Bull 65: 210. Mengele, E.A, ibid; Klein, E and N. Weber (2001) J. Agric. Food Chem. 49: 1224. Hung, W-L, et al. (2011) J. Agric. Food Chem. 1968. Huwiler, A et al. (2012) Br. J. Pharm. 167: 1691. Holmeide, A and L. Skattebol (2000) J. Chem. Soc. Perkin Trans. 1: 2271. But, T and P. Toy (2007) Chem. Asian J. 2: 1340 Swamy, K.C et al. (2009) Chem. Rev. 109: 2551

  In many cases, the Mitsunobu reaction is performed by mixing alcohol, carboxylic reactant and phosphine together in a solvent at low temperature. The azodicarboxylate is then usually added and the reaction is stirred for several hours to react the carboxylic acid with the alcohol to form an ester. The inventors have found that this method produces impurities in the context of the polyunsaturated compounds of the present invention. For example, this reaction sequence often causes undesirable reactions and / or cis / trans isomerism, resulting in obvious impurity peaks on HPLC.

  The inventors have provided a process for the production of polyunsaturated esters or polyunsaturated thioesters and, ultimately, pharmaceutical grade compounds with minimal oxidative and cis / trans isomerization impurities after purification, We are exploring ways to produce the corresponding polyunsaturated ketones.

<Summary of invention>
We have found that the use of the Mitsonobu reaction usually does not yield polyunsaturated ketones with sufficient purity and yield for pharmaceutical use. However, the inventors have clarified that Mitsunobu's chemistry is suitable for medicinal use as long as it uses a specific reaction sequence and reacts in the presence of at least one antioxidant. It has been surprisingly found that it can be used to produce compounds. More specifically, directly producing a pharmaceutically acceptable polyunsaturated ester or polyunsaturated thioester compound in which undesirable oxidation and cis / trans isomerization are substantially reduced or eliminated. We have now found a process that can ultimately be converted to the advantageous ketone compounds described herein. The method practice of the present invention can be used to produce a wide variety of polyunsaturated ketone compounds suitable for pharmaceutical use, including those described herein.

FIG. 1 is an HPLC chromatogram (no area%) showing the results of Experiment 2. FIG. 2 is an HPLC chromatogram (with area%) showing the result of Experiment 2. FIG. 3 is an HPLC chromatogram (no area%) showing the results of Experiment 3. FIG. 4 is an HPLC chromatogram (with area%) showing the results of Experiment 3. FIG. 5 is an HPLC chromatogram (no area%) showing the result of Experiment 4. FIG. 6 is an HPLC chromatogram (with area%) showing the result of Experiment 4. FIG. 7 is an HPLC chromatogram (no area%) showing the result of Experiment 5. FIG. 8 is an HPLC chromatogram (with area%) showing the result of Experiment 5.

  Accordingly, the object of the present invention is to provide a pharmaceutically acceptable multi-agent which can ultimately be converted to the advantageous ketone compounds described herein, substantially reducing or eliminating undesirable oxidation and cis / trans isomerization. It is to produce a polyunsaturated ester or a polyunsaturated thioester compound. The method of the present invention involves the conversion of an alcohol to an ester, more preferably a thioester, using specific Mitsunobu chemistry in the presence of an antioxidant.

  It is also an object of the present invention to provide the target compound in high purity (eg, as often required by administrative agencies). We propose that this can be achieved in the context of Mitsunobu reaction by deprotonating essentially all thioacids or acid nucleophiles during the reaction prior to the addition of the polyunsaturated alcohol. . Also, the beneficial effect is often magnified by combining the polyunsaturated alcohol with at least one pharmaceutically acceptable antioxidant before adding the alcohol to the nucleophile. It is thought that can be done. Surprisingly, the presence of the antioxidant does not affect the success of Mitsunobu.

  Preferably, the next step towards the formation of the polyunsaturated ketone is also carried out in the presence of the same or different pharmaceutically acceptable antioxidants, so that oxidation or cis / trans in the next reaction The possibility of isomerization can be minimized.

  Further, the polyunsaturated alcohol used is produced through contact with a suitable electrophilic reducing agent of polyunsaturated aldehyde under conditions sufficient to produce the polyunsaturated alcohol. Also within the scope of the present invention. It is also believed that the use of a mild electrophilic reducing agent helps to reduce unwanted reduction of double bonds, thereby achieving better purity of the overall synthesis.

Accordingly, from one aspect, the present invention provides a method for producing a polyunsaturated ester or polyunsaturated thioester. The method
(1) In the presence of the phosphine compound and the azodicarboxylate compound in the first container, the carboxylic acid or thioacid is subjected to conditions under which all the carboxylic acid or thioacid in the container essentially deprotonates. Mixing process,
(2) mixing the polyunsaturated alcohol with at least one pharmaceutically acceptable antioxidant in the second container; and (3) contents of the first container and the second container. Mixing to obtain the polyunsaturated ester or polyunsaturated thioester.

From another aspect, the present invention provides a method for producing a polyunsaturated thiol. The method
(1) A step of mixing a polyunsaturated thioic acid in the first container in the presence of a phosphine compound and an azodicarboxylate compound under a condition in which all the thioacids in the container are essentially deprotonated. ,
(2) mixing the polyunsaturated alcohol and at least one pharmaceutically acceptable antioxidant in the second container;
(3) mixing the contents of the first container and the second container to obtain the polyunsaturated thioester;
(4) At least one pharmaceutically acceptable antioxidant that is the same as or different from the antioxidant used in step (2) is added to the polyunsaturated thioester in step (3) to obtain a polyunsaturated thiol. Reducing the thioester of step (3) under conditions sufficient to obtain

From another viewpoint, the present invention provides a method for producing a polyunsaturated ketone compound. The method
(1) A step of mixing a polyunsaturated thioic acid in the first container in the presence of a phosphine compound and an azodicarboxylate compound under a condition in which all the thioacids in the container are essentially deprotonated. ,
(2) mixing the polyunsaturated alcohol and at least one pharmaceutically acceptable antioxidant in the second container;
(3) mixing the contents of the first container and the second container to obtain the polyunsaturated thioester;
(4) At least one pharmaceutically acceptable antioxidant that is the same as or different from the antioxidant used in step (2) is added to the polyunsaturated thioester in step (3) to obtain a polyunsaturated thiol. Reducing the thioester of step (3) under conditions sufficient to obtain
(5) The polyunsaturated thiol is compound (LG) R ³ COX (wherein X is an electron withdrawing group and R ³ is an alkylene group carrying a leaving group (LG)).
(Eg LG-CH ₂ -formation

[Wherein X is an electron withdrawing group and LG is a leaving group])
And reacting in the presence of optionally further added antioxidants to obtain a polyunsaturated ketone compound of formula (II) conceptually defined herein.

  From another aspect, the present invention provides the product of the method defined herein.

From another point of view, the present invention relates to pharmaceutically acceptable 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12. , 15-pentaen-1-yl) thio) propan-2-one is provided. The method
A) In a first container, triphenylphosphine, diisopropyl azodicarboxylate (DIAD) and thioacetic acid are combined in a solvent to form a mixture (preferably at 0-5 ° C for about 10-60 minutes) Reacting the mixture to allow complete deprotonation to occur;
B) (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol and (+/-)-α-tocopherol in a second container Mixing the steps;
C) The contents of the first container and the second container are mixed (preferably 10 minutes to 1 hour) and S-((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9, 12,15-pentaen-1-yl) ethanethioate,
D) subjecting the ester prepared in step C to dry flash chromatography under conditions to purify the ester to a purity determined by HPLC (area%) of at least 90%;
E) contacting the ester prepared and purified in step D with potassium carbonate and (+/−)-α-tocopherol under conditions to reduce the ester group to give the corresponding thiol (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,912,15-pentaene-1-thiol),
F) The thiol produced in Step E and 3-bromo-1,1,1-trifluoroacetone are converted to the ketone.

(Wherein X is CF ₃ ) contacting under conditions for producing
G) comprising purifying the crude ketone produced in step F by dry flash chromatography under conditions that purify the ketone to at least 90% purity as determined by HPLC (area%).

From another point of view, the present invention provides pharmaceutically acceptable 1,1,1-trifluoro-3-(((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12, A process for the preparation of 15-pentaen-1-yl) thio) propan-2-one is provided. The method includes the following steps:
A) In a first vessel, triphenylphosphine, diisopropyl azodicarboxylate (DIAD) and thioacetic acid are combined in a solvent to form a mixture, which is preferably about 10-60 at 0-5 ° C. Reacting for minutes to produce complete deprotonation,
B) Mix (3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaen-1-ol and (+/-)-α-tocopherol in the second container. Process,
C) The contents of the first container and the second container are mixed preferably for 10 minutes to 1 hour, and S-((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9 , 12,15-pentaen-1-yl) ethanethioate,
D) subjecting the ester produced in step C to dry flash chromatography under conditions to purify the ester until the purity determined by HPLC (area%) is at least 90%;
E) contacting the purified ester prepared in step D with potassium carbonate and (+/−)-α-tocopherol to reduce the ester group and the corresponding thiol (3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaene-1-thiol,
F) The thiol produced in step E is crude

[Wherein X is CF ₃ ]
Contacting with 3-bromo-1,1,1-trifluoroacetone under conditions to produce
G) Purifying the crude ketone produced in step F by dry flash chromatography under conditions that purify the ketone to at least 90% purity as determined by HPLC (area%).

  In any method of the present invention, it is further preferred that the polyunsaturated alcohol is obtained by reduction of the corresponding aldehyde in the presence of an electrophilic reducing agent such as DIBAH.

  From another aspect, the present invention provides a pharmaceutical composition comprising the product of the method as defined herein and at least one pharmaceutically acceptable excipient.

<Definition>
The term “polyunsaturated ester or polyunsaturated thioester” refers to a compound comprising multiple double bonds and, of course, a hydrocarbon chain comprising an ester or thioester group.

  Polyunsaturated alcohol refers to a compound containing multiple double bonds and, of course, a hydrocarbon chain containing the alcohol.

  A polyunsaturated ketone refers to a compound containing multiple double bonds and a hydrocarbon chain containing a ketone.

  Thio is a compound containing a -CO-SH group. The carboxylic acid or thioic acid used in step (1) of the method of the present invention is generally a low Mw compound having a Mw of 250 g / mol or less.

  In general, any polyunsaturated ketone of the present invention will have a Mw of less than 500 g / mol, preferably 450 g / mol or less, more preferably 400 g / mol or less.

  The term “pharmaceutically acceptable” is generally non-toxic, biologically undesirable, and useful for producing a medicament suitable for veterinary use and / or human pharmaceutical use. Means that.

<Detailed Description of the Invention>
The present invention relates to a process for producing polyunsaturated esters or polyunsaturated thioesters, and finally polyunsaturated thiols and polyunsaturated ketones. This method provides high yield and purity. In particular, after appropriate purification, the process of the present invention is expected to provide a pharmaceutical grade target compound.

  The present invention provides for the production of polyunsaturated esters or polyunsaturated thioesters under the conditions to provide compounds in the yield and purity often required by regulatory authorities, reducing any thioester to form a thiol, And a method for converting the thiol to a ketone. For example, without being bound by theory, the undesired oxidation products in step (3) above can be reduced or completely removed by deprotonation, and therefore, in step (2) It is believed that essentially all the acid / thioacid is consumed in step (1) prior to the addition of the polyunsaturated alcohol. Thus, the mixing step (3) occurs after essentially all the acid / thioacid reaction in the first step (1).

The starting material of the present invention used in step (2) is a polyunsaturated alcohol. The alcohol is preferably of the formula (I).

R-OH (I)

[Wherein R is an optionally substituted C _9-23 unsaturated hydrocarbon optionally interrupted by one or more heteroatoms or heteroatoms selected from S, O, N, SO, SO _2. And the hydrocarbon group contains at least 2, preferably at least 4 double bonds. ]

  In any group R, the double bond is preferably not conjugated. The group R preferably contains 5 to 9 double bonds, preferably 5 to 8 double bonds, for example 5 to 7 double bonds (eg 5 or 6 double bonds).

  The double bond is preferably not conjugated with a hydroxyl group.

  The double bond present in the group R is in the cis or trans configuration, however, it is preferred that the majority (ie at least 50%) of the double bonds present are in the cis configuration. In a further advantageous embodiment, all double bonds in the group R are in the cis configuration or all two bonds except the double bond closest to the OH group (which may be in the trans configuration). The double bond is in the cis configuration.

  The group R may have 9 to 23 carbon atoms, preferably 11 to 19 carbon atoms, in particular 16 to 18 carbon atoms. The carbon atom is preferably linear in the R group.

  The group R may be interrupted by at least one heteroatom or group of heteroatoms, but this is not preferred, and the group R skeleton preferably contains only carbon atoms.

Said group R may be optionally substituted, for example having up to 3 substituents, such as halo, C _1-6 alkyl (eg methyl), C _1- Selected from ₆ alkoxy. When a substituent exists, the non-polar and small-sized one, for example, a methyl group is preferable. However, it is preferred if the R group is not substituted.

  The R group is preferably linear, that is, it is preferable that there is no branching in the R chain. Natural derivatives such as long chain fatty acids or long chain esters are preferred. In particular, the R group may be derived from arachidonic acid, docosahexaenoic acid or eicosapentaenoic acid.

  Thus, the use of the polyunsaturated alcohol in the present invention may be derived from the corresponding fatty acid or aldehyde (as described below in Scheme 1). Furthermore, we produce a polyunsaturated aldehyde, a suitable electrophilic reducing agent and the polyunsaturated alcohol when the polyunsaturated alcohol is obtained from the corresponding aldehyde. It has also been found that it is preferably obtained in a reaction comprising contacting under conditions sufficient for Without being bound by theory, we believe that a relaxed electrophilic reducing agent reduces the undesirable reduction of double bonds, and as a result, the overall synthesis helps to achieve better yields and purity. It is done.

  The use of diisobutylaluminum hydride (DIBAH) is particularly preferred in this respect. We are surprised that some of the other well known reducing agents (eg, sodium borohydride) have not been successfully used in this reduction because they increase the number of impurities produced. I found it. Surprisingly, the use of DIBAH appears to reduce isomerization and therefore minimize the impurities produced.

  The first step of the method of the present invention includes Mitsunobu chemistry. This reaction typically involves the dissolution of the alcohol, the carboxylic acid and triphenylphosphine in a solvent followed by the addition of an azodicarboxylic acid dissolved in the solvent. However, such a process does not occur in this case.

  In the context of the compounds of the invention, changes in the reaction sequence are proposed in order to avoid oxidation and / or isomerization. It is surprising that the reaction sequence we use gives us the opportunity to produce our target compounds without significant isomerization or oxidation. Thus, prior to our invention, it was not clear that the particular reaction sequence we used could solve the undesirable oxidation and cis / trans isomerization problems. Furthermore, it was even more surprising that the reaction sequence we used worked in the presence of the antioxidant.

Any of the azodicarboxylate and phosphine compounds known for use in the Mitsunobu reaction can be used here. Phosphine is a group of well-known organophosphorus compounds of formula R ′ ₃ P (R = organic derivative, typically an alkyl, aryl or heteroaryl group). An azodicarboxylate is a compound of the general formula R ″ OOC—N═N—COO—R ″, wherein R ″ is an organic derivative such as an alkyl group or an aryl group.

Accordingly, preferred phosphines include the following formula:

PY ₃

[Wherein Y is C1-10 alkyl, C6-10 aryl, C7-12 arylalkyl, C7-12 alkylaryl, C3-10 cycloalkyl, C4-10-heteroaryl, C6-10 aryl O-, Any one of them may be arbitrarily selected with one or more groups selected from NH ₂ , NHR ^a or NR ^a ₂ (wherein R ^a is C 1-6 alkyl). ].

  Suitable heteroaryl groups include pyridine.

  Preferred phosphines for use in the process of the present invention are triarylphosphines (eg, triphenylphosphine) or alkylarylphosphines (eg, dicyclohexylphenylphosphine, diethylphenylphosphine, isopropyldiphenylphosphine, tributylphosphine, tricyclohexylphosphine, triphenylphosphine). Hexylphosphine and tri-n-octylphosphine Other interesting phosphines include 4- (dimethylamino) phenyldiphenylphosphine, diphenyl-2-pyridylphosphine and phenoxydiphenylphosphine. The use of triphenylphosphine) is also particularly preferred.

Preferred azodicarboxylate compounds are of the formula

ZOOC-N = N-COO-Z

Wherein each Z is independently C1-10 alkyl, C6-10 aryl, C7-12 arylalkyl, C7-12 alkylaryl, C4-10-heteroaryl, C4-10-heterocyclic or C3- 10 cycloalkyl, any of which may be optionally substituted with one or more groups selected from halides. Both Z groups are preferably identical. Suitable heteroaryl groups include pyridine. Suitable heterocycles include piperidine or piperazine.

  Suitable azodicarboxylate compounds are optionally substituted C1-6-alkyl esters such as diethyl azodicarboxylate (DEAD), di-tert-butyl azodicarboxylate or diisopropyl azodicarboxylate (DIAD). ) Or optionally substituted aryl esters (eg, di-4-chlorobenzylazodicarboxylate). Other compounds of interest include 1,1 '-(azodicarbonyl) dipiperidine.

  Therefore, in general, the nature of the phosphine and the azodicarboxylate compound used in the method of the present invention is not critical, and any known phosphine or azodicarboxylate agent known in the literature can be used. it can.

The polyunsaturated alcohol reacts with a carboxylic acid or thioacid. The carboxylic acid or thioacid is usually low molecular weight, for example, 250 g / mol or less. The carboxylic acid or thioacid is preferably a monoacid or a monothioacid. Most preferably, the compound R ¹ COOH or R ¹ COSH, wherein R ¹ is a C 1-6 alkyl, C 6-10 aryl group, C 7-12 alkyl aryl group or C 7-12 aryl alkyl group (eg, benzyl or tolyl Is)]. Ideally R ¹ is ethyl or Me, in particular Me.

Accordingly, in the present invention, a compound R-OCOR ¹ or RSCOR ¹ is produced by the reaction of the compound R-OH defined herein with the compound R ¹ COOH or R ¹ COSH.

  Step (2) of the method of the present invention requires the presence of an antioxidant, that is, the presence of a compound that suppresses the oxidation reaction. The antioxidant is preferably a small molecule of 500 g / mol or less, for example, a small molecule of 250 g / mol or less. The antioxidant should ideally be approved for use by the FDA.

  The antioxidant used in step (2) of the method of the present invention is butylhydroxyanisole, butylhydroxytoluene, propyl gallic acid, tocopherol, ascorbic acid, ascorbyl palmitate, thioglycerol, thioglycolic acid, sodium bisulfite, Sodium sulfite, potassium metabisulfite, tetrasodium edetate or EDTA are preferred.

  The use of tocopherol, in particular (+/−)-alpha-tocopherol, is particularly preferred.

  It will be appreciated that the compounds of the present invention are primarily for pharmaceutical use and therefore any antioxidant used is preferably pharmaceutically acceptable.

  The amount of the antioxidant added to the polyunsaturated alcohol may be 0.01 to 1 mol%, 0.1 to 0.5 mol% of the polyunsaturated alcohol.

  The typical Mitsunobu reaction is reported to be complex and controversial with regard to the identification and activity of reaction intermediates. However, as described above, the inventors consumed essentially all of the acid / thioacid in step (3) before adding the polyunsaturated alcohol, yield and more importantly It has been found that the purity of the resulting polyunsaturated ester / thioester can be substantially increased to a level acceptable for many drug applications. They also exist in the presence of pharmaceutically acceptable antioxidants that are not destroyed or otherwise blocked or inactivated by the reagents and conditions used in many Mitsunobu reactions. Was also found to be useful in reducing undesirable cis / trans isomerization in the process of the present invention. It is surprising that the presence of the antioxidant does not affect the success of the reaction. The mechanism by which the Mitsunobu reaction actually works is unclear, but whether the presence of additional reagents, such as antioxidants, buffers many transient intermediate species produced in the reaction, There is always a question mark.

  Typically, a 1: 1: 1 ratio of the reagents can be used in the Mitsunobu reaction. In the claimed process it is necessary to use sufficient phosphine and azodicarboxylate in order to deprotonate the acid or thioacid essentially completely, preferably completely. Thus, in particular, there should be no excess acid or thioacid. In fact, it is preferred that the Mitsunobu reagent used is in excess.

  The reaction of step (1) can be adjusted by using a low temperature, preferably less than 10 ° C., for example, 0 to 5 ° C. The mixture of step (1) is allowed to stand for 10 minutes to 1 hour (eg, at least 20 minutes or at least 30 minutes) to deprotonate the acid or thioacid to its corresponding carboxylate ion or thiocarboxylate ion Ideally, it should be ensured. It is understood that an excess of Mitsunobu reagent should be present relative to the acid or thioacetic acid to ensure complete deprotonation.

  Thus, ideally at least 1.1 molar equivalents of both the phosphine and azocarboxylate reagents are present relative to the acid or thioacid.

  Ideally, the phosphine, azodicarboxylate and acid / thioacid mixture form a solution, particularly a clear solution. There should be no material on the side of the container where the reaction takes place. Since the deprotonation occurs repeatedly, complete deprotonation takes place very quickly (if not less than a few seconds) and reliably within 10 minutes, with precise stirring.

  If complete deprotonation does not occur, it appears in the final product itself in terms of a high level of purity. Without complete deprotonation, more than 10% by weight of impurities can be identified in the final product.

  An advantageous effect in terms of purity is that the polyunsaturated alcohol is added with at least one pharmaceutically acceptable antioxidant in step (2) before adding the alcohol to the reaction material of step (1). It is thought to be enhanced by mixing. These steps, and the subsequent steps for producing the polyunsaturated ketone, are performed in the presence of the same or different pharmaceutically acceptable antioxidants to reduce the possibility of cis / trans isomerization in the reaction. It is preferable to minimize.

  The actual reaction in step (3) of the method of the present invention may take from 10 minutes to 1 hour and may be performed at a convenient temperature, for example, room temperature.

It will be understood that typically the molar amount of polyunsaturated alcohol is relative to the amount of acid or thioacid present.
Once the thioester or ester is formed, it can be worked up in a conventional manner (eg, such as subject to dry flash chromatography). Ideally, the ester or thioester is at least 90% pure as determined by HPLC (area%) at this point. More preferably, the purity is 91% or more, for example 92% or more, ideally 93% or more, especially 94% or even 95% or more.

  The process here has been found to produce the ester or thioester in a high yield, for example, 70% or more. It was also shown in the examples that the presence of impurities detectable by HPLC can be removed.

  In a preferred embodiment, the thioester formed in the method of the invention is then converted itself to the corresponding thiol. This can be done theoretically using any of the usual reduction methods (eg, using diisobutylaluminum hydride), but side reactions and impurity formation and the cis / To avoid trans isomerization, we propose to carry out this reaction in the presence of an antioxidant. The antioxidant is theoretically present in the presence of residual antioxidant from the formation of the thioester and no further antioxidant is required, but is preferably added at this stage. However, typically, any antioxidant added during the formation of the thioester is removed during the purification of the thioester, so additional antioxidants are required.

  The antioxidant may be the same as or different from that added in step (2) of the above method. The antioxidant is butylhydroxyanisole, butylhydroxytoluene, propyl gallate, tocopherol, ascorbic acid, ascorbyl palmitate, thioglycerol, thioglycolic acid, sodium bisulfite, sodium sulfite, potassium metabisulfite, edetate tetrasodium Or it is preferably selected from EDTA.

  The use of tocopherol is particularly preferred. The amount of added / present antioxidant may also be on the order of about 0.01 to 1 mol%, preferably 0.1 to 0.5 mol%, relative to the polyunsaturated thioester present. Good.

  In addition, the advantageous effect is that the polyunsaturated thiol, the polyunsaturated thioester and a suitable mild electrophilic reducing agent, and a condition sufficient to produce the polyunsaturated thiol are obtained. Further enhancement can be achieved by manufacturing in a process that involves contacting. Without being bound by theory, the use of a mild electrophilic reducing agent as described below reduces the undesirable reduction of double bonds, thereby improving overall yield and purity. It is thought that it helps to achieve.

  A suitable reducing agent is ideally a metal carbonate such as potassium carbonate. The use of a solvent such as methanol is suitable.

Thus, according to a further aspect, the present invention provides a method for producing a pharmaceutically acceptable polyunsaturated thiol. This method
(1) mixing a thioic acid in a first container in the presence of a phosphine compound and an azodicarboxylate compound under conditions in which all thioic acids in the container are essentially deprotonated;
(2) mixing the polyunsaturated alcohol and at least one pharmaceutically acceptable antioxidant in the second container;
(3) mixing the contents of the first container and the second container under conditions sufficient to produce the corresponding polyunsaturated thioester;
(4) contacting the polyunsaturated thioester with a second pharmaceutically acceptable antioxidant and reacting the resulting mixture under conditions sufficient to produce the polyunsaturated thiol; Including the step of

Accordingly, preferred thioesters are those of the formula R-SCOR ¹ , wherein R and R ¹ are as defined above. A preferred thiol is simply RSH.

  Ideally, the thiol at this point should be at least 90% pure as determined by HPLC (area%). More preferably, the purity is 91% or more, for example 92% or more, ideally 93% or more, especially 94% or more, even 95% or more.

  The method here has been found to produce thiols in high yields, eg, 70% or higher. Also, as shown in the examples, the presence of impurities detectable by HPLC can be removed.

  Of course, the method of the invention ideally targets a variety of pharmaceutically acceptable polyunsaturated ketones suitable for pharmaceutical use. Preferred compounds include a ketone group containing an electron withdrawing group and a sulfur atom at the α, β, γ or δ position from the ketone group. The electron withdrawing group or EWG attracts the electrons away from the reaction center.

Preferred polyunsaturated ketone targets of the present invention are therefore those of formula (II).

R ² -CO-X (II)

[Wherein R ² is a C _10-24 polyunsaturated hydrocarbon group interrupted by an S atom at the α, β, γ or δ position from the ketone group,
X is an electron withdrawing group (EWG). ]
Suitable electron withdrawing groups X for any of the compounds of the invention are CN, phenyl, CHal ₃ , CHal ₂ H, CHalH ₂ (where Hal means halogen, in particular F). The EWG is in particular CHal ₃ , for example CF ₃ .

  Most preferably, the S atom is beta to the carbonyl.

In any group R ² , the double bond is preferably not conjugated. Said group R ² preferably comprises 5 to 9 double bonds, preferably 5 or 8 double bonds, for example 5 to 7 double bonds, for example 5 or 6 double bonds.

  It is also preferred that the double bond is not conjugated with the hydroxyl group.

Said double bond present in the group R ² may be in the cis or trans configuration, however, the majority (ie at least 50%) of the double bonds present are preferably in the cis configuration. In a further advantageous embodiment, all double bonds in the group R ² are in the cis configuration or all double bonds are most in the S group (which may be in the trans configuration). The cis configuration except for the close double bond.

The group R ² may have 10 to 24 carbon atoms, preferably 12 to 20 carbon atoms, especially 17 to 19 carbon atoms.

  In a preferred embodiment, the present invention provides pharmaceutically acceptable 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12. , 15-pentaen-1-yl) thio) propan-2-one (see also Scheme 1 below)

[Wherein X is CF ₃ ] or related compounds

[Wherein X is CF ₃ ].

Thus, the final step of the method of the invention involves the reaction of the thiol with an appropriate ketone to form the desired compound of formula (II). The reactive ketone compound has the formula (LG) R ³ CO—X [wherein R ³ together with the R group of the polyunsaturated alcohol used in step (2) has the formula (II) Which forms the group R ² in

R ³ is preferably C1-3-alkylene (eg, methylene). LG represents a leaving group. The leaving group is nucleophilically substituted by the thiol group. A leaving group is a molecular fragment that leaves with a pair of electrons in heterogeneous bond cleavage. Of course, (LG) R ³ —COX preferably represents the compound LG—CH ₂ —COX wherein LG is a leaving group (eg, a halide, tosyl, mesyl, etc.). Ideally, LG is a halide (eg, Br). X is an electron withdrawing group as defined in the above formula, and CF ₃ is preferred. (LG) R ³ —COX is most preferably BrCH ₂ —COCF ₃ .

  This final reaction step may be carried out in the presence of further antioxidants as defined herein. Also, the antioxidant may be present inherently because it was carried over from the thioester reduction step, and in that scenario, no additional antioxidants need to be added. However, it is also within the scope of the present invention to add further antioxidants, for example when the thiol formed is purified and thus the antioxidants are removed.

  The use of tocopherol is particularly preferred when an antioxidant is used. The amount of added / present antioxidant may also be about 0.01 to 1 mol%, preferably about 0.1 to 0.5 mol%, relative to the polyunsaturated thiol content. Good.

  It will be appreciated that any of the reactions described herein must be performed in the absence of oxygen, for example, in an Ar atmosphere.

  Ideally, the ketone at this point should be at least 90% pure as determined by HPLC (area%). More preferably, the purity is 91% or more, such as 92% or more, ideally 93% or more, especially 94% or more, even 95% or more.

  It has been found that the process described here produces the ketone in high yields, for example, 70% or higher. Also, as shown in the examples, the presence of impurities detectable by HPLC can be removed.

In the most preferred embodiment, the method of the invention comprises at least the following steps:
A) In a first container, combining phosphine, azodicarboxylate and thioacetic acid in a solvent to form a mixture so that complete deprotonation of said thioacetic acid occurs;
B) Mixing (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol (C18 allyl alcohol) and an antioxidant in the second container. ,
C) Mixing the contents of the first solution and the second container, S-((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaene-1- I) A process for producing ethanethioate.

More particularly, the method of the present invention requires the following steps:
A) combining in a first vessel triphenylphosphine, diisopropyl azodicarboxylate (DIAD) and thioacetic acid in a solvent so that complete deprotonation of said thioacetic acid occurs;
B) Mixing (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol and tocopherol in the second container,
C) The contents of the first container and the second container are mixed, and S-((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaene-1- I) A process for producing ethanethioate.

And the S-((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaen-1-yl) ethanethioate is
D) It is further preferred if the ester is subjected to dry flash chromatography under conditions where the purity determined by HPLC (area%) is purified to at least 90%.

Furthermore, after either step C or D,
E) Said S-((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaen-1-yl) prepared in optionally purified step C or D) Ethanethioate is reduced to the corresponding thiol (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,912,15- with metal carbonate (for example, potassium carbonate) and tocopherol and the ester group is reduced. Pentaene-1-thiol) is preferred when contacted under the conditions to produce.

  And F) the thiol produced in step E,

[Wherein X is CF ₃ ]
It is preferable when contacting with 3-bromo-1,1,1-trifluoroacetone under the conditions for producing

  The compound can be purified in dry flash chromatography to a pharmaceutically acceptable compound to a purity determined by HPLC (area%) of at least 90%.

  In another aspect, the present invention provides pharmaceutically acceptable 1,1,1-trifluoro-3-(((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12, 15-pentaen-1-yl) thio) propan-2-one

Wherein X is CF ₃ , and then the starting alcohol is (3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaene- Provided is the above protocol for appropriate substitution to 1-ol.

  It will be appreciated that the compounds produced in the methods of the invention have a variety of applications, such as the treatment of chronic inflammatory diseases. These are formulated as pharmaceutical compositions using known techniques. No further explanation of such techniques is necessary here.

  The present invention will be described with reference to the following examples and figures, but is not limited thereto.

  1 to 8 are HPLC chromatograms showing the products of the following examples.

<Example>
Example 1: 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaen-1-yl) thio) Overview of Propan-2-one Synthesis The following information provides a general overview of the synthesis of the polyunsaturated ketone. Referring to Scheme 1, Step A and Step B are referred to in more detail in Example 6 below.

All the steps to produce the C18 allyl alcohol (Scheme 1, below) use diisobutylaluminum hydride (DIBAH) in place of sodium borohydride in the reduction of aldehyde to alcohol. Except for use in reducing excess reduction, essentially Chem. Soc. Perkin Trans. 1, 2000, 2271-2276 (Skatebol and Holmeide). During the last three steps (Scheme 1, below), the following measures / changes were made:
All reactions were performed under an argon atmosphere. The lights in the gas hood were turned off. No other measures for light protection were needed. Furthermore, the last three steps (referred to as A, B and C, respectively) are performed in the presence of alpha-tocopherol. The order of reagent addition in the Mitsunobu reaction is considered important to avoid isomerization. It is understood that it is very important that all of the thioacetic acid react completely before the introduction of C18 allyl alcohol. In addition, both the crude and purified product of step (A) were capped with a septum and flushed with argon and placed in a freezer during storage. Step (B) is performed without purification, but the raw product is also stored at −18 ° C. under an argon atmosphere if storage is required. Great care is needed to ensure that both the crude product and the purified material are kept under argon during the last step.

Scheme 1: 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaen-1-yl) thio) propane Overview of 2-one synthesis

Comparative Example 2: Production of a polyunsaturated thioester produces a contaminant that migrates near the main product peak.

  The lights in the gas hood were turned off. Other measures regarding light protection are not considered necessary. Under argon, the following solution was prepared in a 200 ml volumetric flask with a glass stopper.

  (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol ((1), 15.0 g, 57.6 mmol), thioacetic acid (5.00 ml, 70.0 mmol) and alpha-tocopherol (30.4 mg) were combined in anhydrous THF (150 ml). The solution was cooled to 0 ° C.

  In a 1 liter round bottom flask was charged triphenylphosphine (18.1 g, 69.1 mmol) followed by anhydrous THF (300 ml). A stir bar was placed in the flask, flushed with argon, immersed in an ice bath with a septum, and stirred at 0 ° C. for 10 minutes. Diisopropyl azodicarboxylate (13.6 ml, 57.6 mmol) was added in one portion through a septum using a syringe and the reaction mixture was stirred at 0 ° C. for 30 minutes. A pre-cooled solution of (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol, thioacetic acid and alpha-tocopherol in anhydrous THF is added all at once. did. The cooling bath was removed and the reaction mixture was stirred for 1 hour. The clear yellow solution was evaporated under reduced pressure (rotary evaporator) to remove THF. To the residue was added diethyl ether (120 ml) and the flask was rotated on a rotary evaporator for 10 minutes at room temperature. The mixture was filtered using sintered glass (type 3) and the residue was rinsed with ether (2 × 50 ml). The combined furnace liquid was evaporated under reduced pressure (rotary evaporator). To the residue was added heptane (100 ml) and the flask was rotated at room temperature for 10 minutes. Filter through the sintered glass, rinse with heptane (2 × 25 ml) and concentrate to give 24.8 g of the crude product as a yellow oil. Purified by dry flash chromatography and flash chromatography (heptane: EtOAc gradient) and purified with 12.5 grams (68%) of S-((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12, 15-Pentaen-1-yl) ethanethioate was obtained as a colorless oil.

  Figures 1 and 2 show the chromatograms of the products in the synthesis. The by-product can be identified as a shoulder just to the right of the main product peak in FIGS.

  Example 3: Prior to addition of the polyunsaturated alcohol, thioacetic acid is pre-reacted to reduce the presence of contaminants.

  The lights in the gas hood were turned off. Other measures regarding light protection are not considered necessary.

  Triphenylphosphine (6.06 g, 23.1 mmol) is weighed and transferred to a 1 liter round bottom flask equipped with a magnetic stir bar, dissolved in anhydrous THF (300 ml), flushed with argon and stoppered with a septum. And soak in an ice / water bath. The solution is stirred at 3.5 ° C. for 11 minutes.

  Diisopropyl azodicarboxylate (DIAD) (4.50 ml, 20.8 mmol) is added to the reaction mixture in one portion and the mixture is stirred at 0.5 ° C. for 32 minutes.

  Thioacetic acid (1.50 ml, 21 mmol) is added to the reaction mixture in one portion and the mixture is stirred at 3.5 ° C. for 15 minutes.

  Alpha-tocopherol (9.8 mg) and octadeca-2 (E), 6 (Z), 9 (Z), 12 (Z), 15 (Z) -pentaen-1-ol (5.00 g, 19.2 mmol) Was weighed and transferred to an Erlenmeyer flask, dissolved in anhydrous THF (50 mL) and added to the reaction mixture all at once. After the addition, the cooling bath was removed and the mixture was stirred for 47 minutes.

  The reaction mixture was concentrated under reduced pressure. To the residue was added diethyl ether (40 ml) and the flask was rotated on a rotary evaporator for 10 minutes at room temperature. The mixture was filtered through sintered glass (type 3) and the residue was rinsed with ether (2 × 15 ml). The combined filtrates were evaporated under reduced pressure (rotary evaporator). To the residue was added heptane (35 ml) and the flask was rotated at room temperature for 10 minutes at room temperature. Filtration through the sintered glass, rinsing with heptane (2 × 10 ml) and concentration gave a crude product of yellow oil. Purified by dry flash chromatography (heptane: EtOAc gradient) and 4.52 grams (74%) of S-((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaene -1-yl) ethanethioate was obtained as a colorless oil.

  3 and 4 show that no impurities from Example 2 are present.

  Comparative Example 4: Production of a pollutant migrating near the main product peak by production of polyunsaturated trifluoroketone without antioxidant

(2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaene-1-thiol (52.36 g, 189.4 mmol) in ethanol (1200 ml) and water (805 ml). To the solution was added sodium bicarbonate (33.48 g, 397.7 mmol) and the reaction mixture was stirred at room temperature under nitrogen for 15 minutes. 3-Bromo-1,1,1-trifluoroacetone (23.6 ml, 227.3 mmol) was added in one portion. The reaction mixture was stirred for 40 minutes at room temperature under nitrogen, transferred to a separatory funnel and the aqueous phase was extracted with heptane (2 × 1 liter). The organic layer was washed with brine (250 ml), dried (Na ₂ SO ₄ ), filtered and concentrated. 43.19 g (59%) of 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6, by dry flash chromatography (heptane: EtOAc gradient). 9,12,15-pentaen-1-yl) thio) propan-2-one was obtained as a pale yellow oil.

  The following figure shows the product chromatogram in the synthesis of AVX001 in the absence of an antioxidant (alpha-tocopherol). In FIGS. 5 and 6, the contaminant can be seen as a shoulder that has moved closer to the main product peak.

  Example 5: The production of polyunsaturated trifluoroketone using an antioxidant removes the presence of contaminants.

(2E, 6Z, 9Z, 12Z, 15Z) -Octadeca-2,6,9,12,15-pentaene-1-thiol (5.06 g, 18.3 mmol) in ethanol (120 ml) and water (80 ml) To was added sodium bicarbonate (3.23 g, 38.43 mmol) and the reaction mixture was stirred at room temperature under nitrogen for 15 minutes. 3-Bromo-1,1,1-trifluoroacetone (2.3 ml, 22.0 mmol) was added in one portion. The reaction mixture was stirred for 35 minutes at room temperature under nitrogen, transferred to a separatory funnel and the aqueous phase was extracted with heptane (2 × 100 ml). The organic layer was washed with brine (30 ml), dried (Na ₂ SO ₄ ), filtered and concentrated. By flash chromatography (heptane: EtOAc gradient) 5.51 g (78%) of 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9 , 12,15-pentaen-1-yl) thio) propan-2-one as a colorless oil. Figures 7 and 8 show the chromatograms of the products in the synthesis of trifluoroketone in the presence of an antioxidant (alpha-tocopherol). The light in the gas hood was turned off. Other measures regarding light protection are not considered necessary.

Example 6: 1,1,1-trifluoro-3-(((2E, 6Z, 9Z, 12Z, 15Z,)-octadeca-2,6,9,12,15-pentaen-1-yl) thio) Synthesis of Propan-2-one (4) A method for producing the polyunsaturated trifluoroketone is shown below. In order to remove or reduce the presence of undesirable contaminants, the thioic acid was consumed in another reaction before the polyunsaturated alcohol was added. Alpha-tocopherol was also mixed with the alcohol in a separate reaction vessel to reduce or eliminate unwanted oxidation. These steps and others shown below have been found to increase the yield and purity of the compound to 93% or more (area%).
A. Step A (see Scheme 1 above)
Weigh triphenylphosphine (6.05 g ± 0.10 g), transfer to a 1 liter round bottom flask equipped with a magnetic stir bar, dissolve in anhydrous THF (310 mL ± 15 mL), flush with argon, septum And then immersed in an ice / water bath. The solution was stirred at 0-5 ° C. for 10-20 minutes. Diisopropyl azodicarboxylate (DIAD) (4.55 mL ± 0.09 mL) was added in one portion to the reaction mixture. The mixture was stirred at 0-5 ° C. for 30-40 minutes. Thioacetic acid (1.50 mL ± 0.03 mL) (A) was added to the reaction mixture in one portion. The mixture was stirred at 0-5 ° C. for 15-20 minutes.

  Alpha-tocopherol (10 mg ± 0.2 mg) and octadeca-2 (E), 6 (Z), 9 (Z), 12 (Z), 15 (Z) -pentaen-1-ol (C-18 alcohol) ( A) was weighed (5.00 g ± 0.10 g), transferred to an Erlenmeyer flask, dissolved in anhydrous THF (50 mL ± 2.5 mL), and added to the reaction mixture in one portion.

  After the addition, the cooling bath was removed and the mixture was stirred for 45-55 minutes. The reaction mixture was concentrated under reduced pressure. The temperature in the water bath was 30 ° C. or lower. The resulting crude product was analyzed by HPLC (see below). The residue was flushed with argon, capped with a septum and placed in the freezer.

  This synthesis was performed three times and the batches were combined and subjected to chromatographic purification.

  [Purification] Only those crude products that passed the acceptance criteria were combined. To the residue was added heptane (50 mL ± 2.5 mL) and the flask was rotated on a rotor vapor for 5-15 minutes at room temperature. The mixture was filtered through a sintered glass funnel (grade 3). Heptane (25 ml ± 1 mL) was added to the reaction flask, vortexed and filtered through a sintered glass funnel. The precipitate was washed with heptane (25 ml ± 1 mL). The filtrate and the washing solution were concentrated under reduced pressure, and the temperature in the water bath was 30 ° C. or lower. The residue was flushed with argon, capped with a septum and stored in a freezer.

[Dry Flash Chromatography] Silica gel (500 g ± 25 g) was transferred to a 1000 mL sintered glass funnel (grade 3) and pre-eluted with 500 mL heptane. 20-40 mL of heptane was added to the crude product and the mixture was loaded on the column. The column was eluted with 250 mL ± 25 mL fractions. The 250 mL stepped Erlenmeyer flask was accurate enough for this purpose. In preparing the heptane: EtOAc (100: 1) eluent, it is accurate enough to add 25 mL of EtOAc to the pre-sealed 2500 mL heptane flask. Fractions were analyzed by TLC (eluent heptane: EtOAc 95: 5). Products with an R _f of about 0.4 were stained with PMA or ammonium molybdate / cerium sulfate immersion. The elution was continued until the entire product exited the column. The product is present at a purity of 93% or more (area%), the peak of RRT = 1.03 is 4% or less (area%), and the peak of RRT = 0.59 is 1% or less (area%). A fraction was collected. The material was transferred to a 1 liter round bottom flask and evaporated under reduced pressure to a temperature ≦ 35 ° C. to give the product 13.5 (73.8%) as a colorless oil. The product was stored at about −18 ° C. under an argon atmosphere.

B. Synthesis Step B-See Scheme 1 above [Preparation of Solution] Concentrated HCl (12.3 ± 0.25 mL) is added to a 250 mL graduated cylinder containing some tap water and marked with additional tap water (150 mL). Filled and mixed. NaCl (≧ 40 g) was mixed with tap water (110 mL ± 10 mL) in an Erlenmeyer flask. The lights in the gas hood were turned off. I did not think that other measures for light protection were necessary. Alpha-tocopherol (27.2 mg) is weighed, MeOH (130 ml) is weighed and dissolved, and thioacetic acid S-octadeca-2 (E), 6 (Z), 9 (Z), 12 (Z), Transferred to a 1 liter round bottom flask equipped with a magnetic stir bar and 100 ml dropping funnel containing 15 (Z) -pentaenyl ester (13.5 g). K ₂ CO ₃ (6.45 g) was added to the reaction mixture all at once. Flush with argon and plug with a septum. Stir at room temperature for 30-40 minutes. The reaction flask was immersed in an ice / water bath and 1M HCl (150 mL) was carefully added using a dropping funnel, then transferred to a separatory funnel and extracted with heptane [2 × 200 mL]. The combined organic phases were washed with brine (100 mL), transferred to an Erlenmeyer flask equipped with a magnetic stir bar, and Na ₂ SO ₄ (70.4 g) was added. If necessary, additional Na ₂ SO ₄ was added. The suspension was stirred for 10-20 minutes. The suspension was filtered and the filter cake was rinsed with heptane (≧ 25 mL), transferred to a 1 L round bottom flask and evaporated under reduced pressure at temperature ≦ 35 ° C. This crude product (12.0 g, quantitative yield) was used in the next step without further purification. This product was stored at −18 ° C. or lower under an argon atmosphere.

C. Production of polyunsaturated trifluoroketone (see Scheme 1)
[Preparation of solution]
NaCl (≧ 40 g) was mixed with tap water (I) (110 mL). The light in the gas hood was turned off. I did not think that other measures for light protection were necessary. NaHCO ₃ (7.68 g) was weighed, EtOH (290 mL) and tap water (192 mL) were measured, and Octadeca-2 (E), 6 (Z), 9 (Z), 12 (Z), 15 (Z ) -Pentaene-1-thiol (12.0 g) was transferred to a 1 liter flask and flushed with argon. Stir vigorously for 15-20 minutes at room temperature. 3-Bromo-1,1,1-trifluoroacetone (5.4 mL) was added in one portion and stirred vigorously for 35-45 minutes. The material was transferred to a separatory funnel and extracted with heptane (I) (2 × 200 mL). The combined organic phases were washed with brine (100 mL), transferred to an Erlenmeyer flask equipped with a magnetic stir bar, and Na ₂ SO ₄ (I) (60 g) was added. If necessary, additional Na ₂ SO ₄ may be added. The suspension was stirred for 10-20 minutes.

  The suspension was filtered and the filter cake was rinsed with heptane (≧ 25 mL), transferred to a 1 L round bottom flask and evaporated at reduced temperature (≦ 35 ° C.).

[Dry Flash Chromatography] Silica (500 g ± 25 g) was transferred to a 1000 mL sintered glass funnel (grade 3). Pre-eluted with heptane 500 ± 25 mL. 20-25 mL of heptane was added to the crude product and the mixture was loaded on the column. The column was eluted with 350 mL ± 20 mL fractions. The graded 500 mL Erlenmeyer flask was sufficiently accurate for this measurement. In preparing the heptane: EtOAc (100: x) eluent, it was accurate enough to add 25 x mL of EtOAc to the pre-sealed 2500 mL heptane flask. Fractions were analyzed by TLC (eluent heptane: EtOAc 80:20). Products with an R _f of about 0.26 were stained with PMA or ammonium molybdate / cerium sulfate immersion. The elution was continued until the entire product exited the column. Elution with heptane-heptane: EtOAc (100: 1)-(100: 2)-(100: 3)-(100: 10). If impurities exit the column after fraction # 21 but before the product, (100: 10) may be used from fraction # 22 or continued with (100: 2) or (100: 3) Good. (100: 10) may be used when impurities before the product exit the column.

  Fractions that are pure by TLC or have only a small amount of impurities are analyzed by HPLC. Fractions containing product with purity (area%) within the HPLC spectrum are collected. The material was transferred to a 1 liter round bottom flask and evaporated under reduced pressure at a temperature ≦ 35 ° C. When the pressure was equilibrated, the rotababe was filled with argon. Using heptane, it was transferred through a folding filter paper to a 250 mL round bottom flask and evaporated under reduced pressure at temperature (≦ 35 ° C.). When the initial evaporation was complete, a high vacuum pump was connected to the rotorbavel and evaporated for 1-2 hours to give 10.29 g (61%) of product as a colorless oil. The product was stored at −18 ° C. or lower under an argon atmosphere.

  The following materials and methods were used as needed in this Example 6.

  1. TLC: A small amount of product was analyzed in need of TLC, eluting with heptane: EtOAc (80:20). Product Rf, about 0.26, stained with PMA immersion or ammonium molybdate / cerium sulfate immersion. Only a small amount of impurities was tolerated.

2-HPLC
HPLC / UV condition analysis column: EC-C18, 150 × 4.6 mm, 2.7 μm Particle size flow rate: 1.5 ml / min Stop time: 22 minutes Temperature: 15 ° C.
Detector: UV 210: 8 ref 360: 100 PW> 0.05 min Mobile phase: A: ACN / water 70:30 w / 0.02% v / v formic acid B: ACN w / 0.02% v / v Formic acid mobile phase gradient program:

Claims (27)

A method for producing a polyunsaturated thioester, the method comprising:
(1) In the first container, in the presence of a phosphine compound and an azodicarboxylate compound, thiol acid of formula R ¹ CASH (where R ¹ is ethyl or methyl) is added to all the thiol acids in the container. Mixing under conditions that essentially deprotonate,
(2) mixing the polyunsaturated alcohol and at least one pharmaceutically acceptable antioxidant in the second container;
(3) A method comprising a step of mixing the contents of the first container and the second container to obtain the polyunsaturated thioester. A method for producing a polyunsaturated thiol, the method comprising:
(1) In the first container, in the presence of a phosphine compound and an azodicarboxylate compound, thiol acid of formula R ¹ CASH (where R ¹ is ethyl or methyl) is added to all the thiol acids in the container. Mixing under conditions that essentially deprotonate,
(2) mixing the polyunsaturated alcohol and at least one pharmaceutically acceptable antioxidant in the second container;
(3) mixing the contents of the first container and the second container to obtain a polyunsaturated thioester;
(4) adding at least one pharmaceutically acceptable antioxidant identical or different from the antioxidant used in step (2) to the polyunsaturated thioester of step (3), Reducing the thioester of step (3) under conditions sufficient to obtain a thiol. A method for producing a polyunsaturated ketone compound, the method comprising:
(1) In the first container, in the presence of a phosphine compound and an azodicarboxylate compound, thiol acid of formula R ¹ CASH (where R ¹ is ethyl or methyl) Mixing under essentially deprotonating conditions,
(2) In a second container, a polyunsaturated alcohol of formula ROH (wherein R is a C9-23-polyunsaturated hydrocarbon) and at least one pharmaceutically acceptable antioxidant. The process of mixing with
(3) mixing the contents of the first container and the second container to obtain a polyunsaturated thioester;
(4) At least one pharmaceutically acceptable antioxidant that is the same as or different from the antioxidant used in step (2) is added to the polyunsaturated thioester in step (3) to obtain a polyunsaturated thiol. Reducing the thioester of step (3) under conditions sufficient to obtain RSH;
(5) The polyunsaturated thiol is converted into compound (LG) R ³ COX (wherein X is an electron withdrawing group and R ³ is a C _1-3 alkylene group carrying a leaving group LG) A method comprising a step of reacting in the presence of an optionally added antioxidant to obtain a polyunsaturated ketone compound.   The method according to any one of claims 1 to 3, wherein the pharmaceutically acceptable antioxidant is tocopherol.   The method according to claim 1, wherein the polyunsaturated thioester has a purity determined by HPLC (area%) of at least 90%.   6. The method of claim 5, wherein the polyunsaturated thioester has a purity determined by HPLC (area%) of at least 91%, 92%, 93%, 94% or at least 95%.   4. The method of claim 3, wherein the polyunsaturated ketone has a purity determined by HPLC (area%) of at least 90%.   8. The method of claim 7, wherein the polyunsaturated ketone has a purity determined by HPLC (area%) of at least 91%, 92%, 93%, 94% or at least 95%.   The method according to claim 1, wherein the phosphine is triphenylphosphine.   The method according to claim 1, wherein the azodicarboxylate is diisopropyl azodicarboxylate (DIAD).   The method according to claim 1, wherein in step (1), the phosphine and the azodicarboxylate are in molar excess with respect to the thiolic acid. The method according to claim 1, wherein the polyunsaturated alcohol is an alcohol of the formula (I).
R-OH (I)
[Wherein R is an optionally substituted C _9-23 unsaturated hydrocarbon optionally interrupted by one or more heteroatoms or heteroatoms selected from S, O, N, SO, SO _2. And the hydrocarbon group contains at least two double bonds. ]   The method according to claim 1, wherein the polyunsaturated alcohol is a C18 alcohol containing 5 double bonds.   14. The method of claim 13, wherein the polyunsaturated alcohol is (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol.   15. The method according to any one of claims 1 to 14, wherein the polyunsaturated thioester is a C18 polyunsaturated thioacetate containing 5 double bonds.   The polyunsaturated thioacetate is S-((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-yl) ethanethioate. 15. The method according to 15. 4. The method of claim 3, wherein the polyunsaturated ketone compound is a compound of formula (II).
R ² -CO-X (II)
[Wherein R ² is a C _10-24 polyunsaturated hydrocarbon group interrupted by an S atom at the β, γ or δ position from the ketone group,
X is an electron withdrawing group. ] A) In a first vessel, phosphine, azodicarboxylate and thioacetic acid are combined in a solvent to form a mixture, so that complete deprotonation of said thioacetic acid occurs;
B) Mixing (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-ol (C18 allyl alcohol) and an antioxidant in the second container. ,
C) Mixing the contents of the first container and the second container, S-((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-yl 2. The method of claim 1 comprising the step of producing ethanethioate. D) subjecting the ester produced in step C to dry flash chromatography under conditions that purify the ester to a purity determined by HPLC (area%) of at least 90%;
E) S-((2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaen-1-yl) prepared in Step C or Step D and optionally purified Conditions under which ethanethioate reduces the ester group to produce the corresponding thiol (2E, 6Z, 9Z, 12Z, 15Z) -octadeca-2,6,9,12,15-pentaene-1-thiol) 19. The method of claim 18, further comprising optionally contacting the metal carbonate and tocopherol. 20. The method of claim 19, further comprising the step of contacting the thiol produced in step E with 3-bromo-1,1,1-trifluoroacetone under conditions to produce:
[Wherein X is CF ₃ . ] The method according to claim 3 or 17, wherein the polyunsaturated ketone is:
[Wherein X is CF ₃ . ]   The method according to any one of claims 1 to 17, wherein the polyunsaturated alcohol is obtained by reduction of the corresponding aldehyde in the presence of an electrophilic reducing agent. In the step (2), the polyunsaturated alcohol is (3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaen-1-ol,
The S-((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaen-1-yl) thioester is produced by the mixing step (3). Method. (1) combining, in a first container, phosphine, azodicarboxylate and thioacetic acid in a solvent to form a mixture so that complete deprotonation of said thioacetic acid occurs;
(2) In the second container, (3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaen-1-ol (C18 allyl alcohol) and an antioxidant are mixed. Process,
(3) Mixing the contents of the first solution and the second container, S-((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaene-1- The process according to claim 1, comprising the step of producing yl) ethanethioate. At least one pharmaceutically acceptable S-((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaen-1-yl) thioester of the above step (3). Adding an antioxidant that is the same or different from the antioxidant used in step (2),
The thioester of step (3) is reduced under conditions sufficient to produce (3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaene-1- thiol 24. The method of claim 23, comprising: (4) subjecting the ethanethioate produced in step (3) to dry flash chromatography under conditions to purify the ester until the purity determined by HPLC (area%) is at least 90%; And (5) optionally purified S-((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3,6,9,12,15-pentaene produced in step (3) or (4) above -1-yl) ethanethioate is contacted with metal carbonate and tocopherol under conditions to reduce the ester group and the corresponding thiol ((3Z, 6Z, 9Z, 12Z, 15Z) -octadeca-3, 25. The method of claim 24, optionally comprising producing 6,9,12,15-pentaene-1- thiol ). Said polyunsaturated ketone:
(Wherein X is CF ₃ )
27. The method according to claim 25 or 26, comprising the step of contacting 3-bromo-1,1,1-trifluoroacetone with the thiol under conditions to produce